基于多阶调制相位恢复成像的高功率激光精密在线测量技术研究

In order to solve the international problem of accurate on-line wave diagnostics for high power laser facilities (HPLF), including SG series in China, a new wave diagnostic technology based on the previous research work about coherent modulation imaging was proposed. Compared with the previous phase retrieval algorithm, the signal-to-noise ratio (SNR) of reconstructed near-field intensity was enhanced obviously due to the newly developed wave modulator, novel setup and efficient iterative engine. It has the advantages of compact structure, small size, high accuracy, and multiple parameter diagnostics and will satisfy the urgent requirements on accurate on-line wave diagnostics technology in HPLF. A new binary wave modulator was designed with novel structures to provide more high-order wave modulations with additional information redundancy. The accurate segmentation of multiple sub-patterns was achievable with newly developed setup. The noise of the reconstructions was suppressed dramatically by multiple constraints and new iterative engine. The absence of high-order diffraction and the restricted resolution due to a virtual hole in previous algorithm were solved absolutely and it not only could be used for the performance improvement of HPLF in China, but also could be extended to other wavelengths and applied to synchrotron radiation facilities as a new technique for wave diagnostic and phase imaging during the constructions and routine operations.

针对高功率激光驱动器（包括我国“神光”系列）输出光束一直难以精密在线检测这一国际技术难题，本项目在申请人前期研究的基于“调制成像”的检测技术基础上，通过设计新的核心元件、搭建新的检测光路及发展新的波前重建理论，大幅度提高重建光束的近场信噪比，研究出一种结构紧凑、体积小巧、高测量精度及多参数同时诊断的光束检测新技术，为彻底解决高功率激光在线检测问题奠定了技术基础。设计新的二元波前调制元件，实现单次记录的高冗余度多阶调制；搭建新的紧凑型光路，实现多阶频谱的空间分离记录；发展新的波前重建算法，用多阶频谱强度约束实现对重建噪声高效抑制。所研究出的技术可从根本上克服原有方法中的高频信息丢失和重建精度受“虚拟孔”限制这两个主要技术缺陷，不仅能直接用于我国高功率激光驱动器以促进其综合性能的提升，还可推广至其它波段并应用于同步辐射等相关大科学装置，为其建造和平稳运行提供新的在线监测工具和成像方法。

高功率激光驱动器（包括我国“神光”系列）输出光束一直难以实现对光强和相位信息的精密在线检测，这限制了我国高功率激光驱动器的发展，为此本项目在申请人前期研究的基于“调制成像”的检测技术基础上，通过设计新的核心元件、搭建新的检测光路及发展新的波前重建理论，大幅度提高重建光束的近场信噪比，研究出一种结构紧凑、体积小巧、高测量精度及多参数同时诊断的光束检测新技术，为彻底解决高功率激光在线检测问题奠定了技术基础。主要研究内容有：1）设计并优化多阶衍射增强的波前调制器；2）发展新型光场重建算法；3）完成系统优化并实现三倍频光束的在线测量。. 本项目不仅完成了核心期间的设计优化、相关算法的提出，并完成样机、首次实现在神光装置上对三倍频光束近远场信息的在线诊断，使得高功率激光驱动器全链路测量成为可能。